Slow-Moving Landslides a Growing, but Ignored, Threat to Mountain Communities

Typography

As urban centers in mountainous regions grow, more people are driven to build on steeper slopes prone to slow-moving landslides, a new study finds. 

As urban centers in mountainous regions grow, more people are driven to build on steeper slopes prone to slow-moving landslides, a new study finds. Slow-moving landslides are frequently excluded from estimates of landslide risk, but they could threaten hundreds of thousands of people globally, the researchers conclude.

Slow-moving landslides can move as little as one millimeter per year and up to three meters per year. Slopes with slow-moving landslides may seem safe to settle on; the slide itself may be inconspicuous or undetected altogether.

As the slide creeps along, houses and other infrastructure can be damaged. The slow slide can accelerate abruptly, likely in response to changes in precipitation. Sudden acceleration can worsen damage and, in rare cases, lead to fatalities.

Those same slopes may be repopulated years later due to pressure from urban growth, especially when floods drive people from lower-elevation areas. Nearly 1.3 billion people live in mountainous regions, according to the IPCC, and that number is growing.

Read more at American Geophysical Union

Image: Villages on a slow-moving landslide in the Poqueira Valley, Spain. (Credit: Cristina Reyes Carmona)